Display device and semiconductor substrate

ABSTRACT

According to one embodiment, a semiconductor substrate including, a switching element, a first organic insulating film, first and second metal lines arranged in a first direction and extending in a second direction, and a metal electrode located between the first and second metal lines. The first organic insulating film includes first and second surfaces. The switching element is covered with the first surface. The first and second metal lines and the metal electrode are located on the second surface side. The first metal line includes a first portion extending in the second direction and a second portion having a width larger than a width of the first portion. The second portion includes arcuate first and second edge. The metal electrode has a polygonal shape having n corners or an elliptic shape where n is larger than four.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromJapanese Patent Application No. 2020-048058, filed Mar. 18, 2020, theentire contents of which are incorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device and asemiconductor substrate.

BACKGROUND

Recently, various display devices in which touch sensors areincorporated have been proposed. In one example, a display devicestructured such that electrodes formed on a display panel serve assensor electrodes in a touch sensing mode, and serve as commonelectrodes in a display mode has been disclosed. As a touch sensingmethod, either mutual capacitive sensing or self capacitive sensing isapplied. In the touch sensing mode, sensing is carried out as a touchdrive voltage is applied to the sensor electrode through a signal line.

In addition, a structure of a display device comprising a touch sensorhaving sensor electrodes in an insular shape arrayed in a matrix,wherein a pixel electrode is connected to a semiconductor layer viaelectrodes of three layers, i.e., a drain electrode in the same layer asa signal line, a metal electrode in the same layer as a metal line, anda transparent electrode in the same layer as a sensor electrode, isknown.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an appearance of a display device of theembodiments.

FIG. 2 is a plan view showing a configuration example of a touch sensor.

FIG. 3 is a plan view showing a relationship between a pixel and asensor electrode shown in FIG. 2.

FIG. 4 is a view showing a basic configuration of a pixel and anequivalent circuit.

FIG. 5 is a plan view showing an example of a pixel layout.

FIG. 6 is a plan view showing a metal line of the embodiments, and ashape of a metal electrode.

FIG. 7 is a cross-sectional view showing a display panel taken alongline A-B shown in FIG. 6.

FIG. 8 is a plan view showing a positional relationship among the metalline and the metal electrode shown in FIG. 6 and a light-shieldinglayer.

FIG. 9 is a plan view showing shapes of a semiconductor layer and adrain electrode.

FIG. 10 is a plan view showing a positional relationship between thedrain electrode shown in FIG. 9 and the light-shielding layer.

FIG. 11 is a plan view showing shapes of a common electrode andtransparent electrodes.

FIG. 12 is a cross-sectional view showing a first substrate taken alongline C-D shown in FIG. 11.

FIG. 13 is a plan view showing a position of a spacer.

FIG. 14 is a cross-sectional view showing a display panel taken alongline E-F shown in FIG. 13.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided asemiconductor substrate including, a switching element, a first organicinsulating film covering the switching element, a first metal line and asecond metal line arranged in a first direction and extending in asecond direction intersecting the first direction, and a metal electrodein an insular shape located between the first metal line and the secondmetal line. The first organic insulating film includes a first surfaceand a second surface on a side opposite to the first surface. Theswitching element is covered with the first surface. The first metalline, the second metal line, and the metal electrode are located on thesecond surface side. The first metal line includes a first portionextending in the second direction and a second portion having a widthlarger than a width of the first portion. The second portion includes anarcuate first edge and an arcuate second edge located on a side oppositeto the first edge, in planar view. The metal electrode has a polygonalshape having n corners or an elliptic shape where n is larger than four.

According to another embodiment, there is provided a display deviceincluding a scanning line extending in the first direction, a signalline extending in a second direction intersecting the first direction, afirst insulating film covering the signal line, a first metal linearranged on the first insulating film and extending while overlaid onthe signal line, a metal electrode in an insular shape arranged on thefirst insulating film and formed of a same material as the first metalline, a second insulating film covering the first metal line and themetal electrode, a first common electrode located on the secondinsulating film, and a light-shielding layer including a firstlight-shielding portion overlaid on the scanning line and extending inthe first direction and a second light-shielding portion overlaid on thesignal line and extending in the second direction. The first metal lineincludes a first portion overlaid on the second light-shielding portionand extending in the second direction and a second portion overlaid onthe first light-shielding portion and having a width larger than a widthof the first portion. The first common electrode is in contact with thesecond portion through a first contact hole formed in the secondinsulating film at a position overlaid on the second portion. The secondportion includes an arcuate first edge and an arcuate second edgelocated on a side opposite to the first edge, in planar view.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is merely an example, and properchanges in keeping with the spirit of the invention, which are easilyconceivable by a person of ordinary skill in the art, come within thescope of the invention as a matter of course. In addition, in somecases, in order to make the description clearer, the widths,thicknesses, shapes and the like, of the respective parts areillustrated schematically in the drawings, rather than as an accuraterepresentation of what is implemented. However, such schematicillustration is merely exemplary, and in no way restricts theinterpretation of the invention. In addition, in the specification anddrawings, structural elements which function in the same or a similarmanner to those described in connection with preceding drawings aredenoted by like reference numbers, detailed description thereof beingomitted unless necessary.

First, a display device DSP according to the embodiments will bedescribed in detail. In the embodiments, a liquid crystal display deviceis exemplified as the display device DSP.

FIG. 1 is a plan view showing an appearance of a display device DSP ofthe embodiments.

For example, the first direction X, the second direction Y, and thethird direction Z are orthogonal to each other but may intersect at anangle other than 90 degrees. The first direction X and the seconddirection Y correspond to the directions parallel to the surface of asubstrate which constitutes the display device DSP, and the thirddirection Z corresponds to the thickness direction of the display deviceDSP. In the present specification, a direction toward a tip of an arrowindicating the third direction Z is referred to as upward (or merelyabove), and a direction toward the opposite side from the pointing endof the arrow is referred to as downward (or merely below). In addition,an observation position at which the display device DSP is observed isassumed to be located on the side of the arrow tip indicating the thirddirection Z, and viewing from the observation position toward the X-Yplane defined by the first direction X and the second direction Y isreferred to as a planar view.

A plan view of the display device DSP in the X-Y plane is illustrated.The display device DSP comprises a display panel PNL, a flexible printedcircuit 1, an IC chip 2, and a circuit board 3.

The display panel PNL is a liquid crystal display panel, and comprises afirst substrate SUB1, a second substrate SUB2, a sealant SE, alight-shielding layer BM, spacers SP1 to SP4, and a liquid crystal layerLC to be described later. In addition, the display panel PNL comprises adisplay portion DA on which an image is displayed and a non-displayportion NDA in a frame shape surrounding the display portion DA. Thesecond substrate SUB2 is opposed to the first substrate SUB1. The firstsubstrate SUB1 includes a mounting portion MA which extends in thesecond direction Y more than the second substrate SUB2. The firstsubstrate SUB1 is a semiconductor substrate comprising thin-filmtransistors as described later and is also referred to as an arraysubstrate. The second substrate SUB2 comprises color filters asdescribed later and is also referred to as a color filter substrate.

The sealant SE is located in the non-display area NDA to bond the firstsubstrate SUB1 and the second substrate SUB2. The light-shielding layerBM is located in the non-display portion NDA. The sealant SE is providedat a position overlaid on the light-shielding layer BM in planar view.In FIG. 1, an area where the sealant SE is arranged and an area wherethe light-shielding layer LS is arranged are represented by differenthatch lines, and an area where the sealant SE and the light-shieldinglayer LS are overlaid is represented by crosshatching. Thelight-shielding layer BM is provided on the second substrate SUB2.

The spacers SP1 to SP4 are all located in the non-display portion NDA.The spacer SP1 is located in the outermost periphery of the displaypanel PNL. The spacer SP2 is located on a side closer to the displayportion DA than the spacer SP1. The spacers SP1 and SP2 are overlaid onthe sealant SE. The spacers SP3 and SP4 are located on a side closer tothe display portion DA than the sealant SE.

The display portion DA is located at an inner side surrounded by thelight-shielding layer BM. The display panel PNL comprises pixels PXarrayed in a matrix in the first direction X and the second direction Y,in the display portion DA.

The flexible printed circuit 1 is mounted on a mounting portion MA andis connected to the circuit board 3. The IC chip 2 is mounted on theflexible printed circuit 1. Incidentally, the IC chip 2 may be mountedon the mounting portion MA. A display driver DD which outputs a signalnecessary for image display in a display mode of displaying an image isincorporated in the IC chip 2. In addition, in the example illustrated,a touch controller TC which controls a touch sensing mode of detectingapproach or contact of an object to the display device DSP, isincorporated in the IC chip 2. In the drawing, the IC chip 2 isrepresented by a one-dot chain line, and the display driver DD and thetouch controller TC are represented by dotted lines.

The display panel PNL of the present embodiment may be a transmissivedisplay panel having a transmissive display function of displaying animage by selectively transmitting light from a rear surface of the firstsubstrate SUB1, a reflective display panel having a reflective displayfunction of displaying an image by selectively reflecting light from afront surface of the second substrate SUB2, or a transflective displaypanel having the transmissive display function and the reflectivedisplay function.

In addition, the details of the configuration of the display panel PNLare not explained here, but the display panel PNL may have aconfiguration corresponding to any one of a display mode using a lateralelectric field produced along the substrate main surface, a display modeusing a longitudinal electric field produced along the normal of thesubstrate main surface, a display mode using an inclined electric fieldwhich is tilted obliquely with respect to the substrate main surface,and a display mode using an appropriate combination of the above lateralelectric field, longitudinal electric field, and inclined electricfield. The main surface of the substrate is a surface parallel to an X-Yplane defined by the first direction X and the second direction Y.

FIG. 2 is a plan view showing a configuration example of a touch sensorTS. A self-capacitive touch sensor TS will be described below. However,the touch sensor TS may be a mutual-capacitive sensor.

The touch sensor TS comprises sensor electrodes Rx (Rx1, Rx2, etc.)arrayed in a matrix, and sensor lines L (L1, L2, etc.). The sensorelectrodes Rx are located in the display portion DA and arrayed in amatrix in the first direction X and the second direction Y. A sensorelectrode Rx constitutes one sensor block B. The sensor block B is theminimum unit capable of performing the touch sensing. The sensor lines Lextend in the second direction Y and are arranged in the first directionX in the display portion DA. Each of the sensor lines L is provided at,for example, a position overlaid on a signal line S to be describedlater. In addition, each of the sensor lines L is drawn to thenon-display portion NDA and is electrically connected to the IC chip 2via the flexible printed circuit 1.

The relationship between the sensor lines L1 to L3 arranged in the firstdirection X and the sensor electrodes Rx1 to Rx3 arranged in the seconddirection Y will be focused here. The sensor line L1 is overlaid on thesensor electrodes Rx1 to Rx3 and is electrically connected to the sensorelectrode Rx1.

The sensor line L2 is overlaid on the sensor electrodes Rx2 and Rx3 andis electrically connected to the sensor electrode Rx2. A dummy line D20is remote from the sensor line L2. The dummy line D20 is overlaid on thesensor electrode Rx1 and is electrically connected to the sensorelectrode Rx1. The sensor line L2 and the dummy line D20 are located onthe same signal line.

The sensor line L3 is overlaid on the sensor electrode Rx3 and iselectrically connected to the sensor electrode Rx3. A dummy line D31 isoverlaid on the sensor electrode Rx1 and is electrically connected tothe sensor electrode Rx1. A dummy line D32 is remote from the dummy lineD31 and the sensor line L3. The dummy line D32 is overlaid on the sensorelectrode Rx2 and is electrically connected to the sensor electrode Rx2.The sensor line L3, and the dummy lines D31 and D32 are located on thesame signal line.

In the touch sensing mode, the touch controller TC applies a touch drivevoltage to the sensor lines L. The touch drive voltage is therebyapplied to the sensor electrodes Rx and sensing is performed with thesensor electrodes Rx. A sensor signal corresponding to a result ofsensing with each of the sensor electrodes Rx is output to the touchcontroller TC via the sensor line L. The touch controller TC or anexternal host detects occurrence of approach or contact of an object tothe display device DSP, and the position coordinates of the object, onthe basis of the sensing signal.

Incidentally, in the display mode, the sensor electrode Rx functions asa common electrode CE to which a common voltage (Vcom) is applied. Thecommon voltage is applied from, for example, a voltage supply unitincluded in the display driver DD via the sensor lines L.

FIG. 3 is a plan view showing a relationship between the sensorelectrode Rx shown in FIG. 2 and the pixel PX. In FIG. 3, a directionintersecting the second direction Y counterclockwise at an acute angleis defined as direction D1, and a direction intersecting the seconddirection Y clockwise at an acute angle is defined as direction D2.Incidentally, angle θ1 made between the second direction Y and thedirection D1 is substantially the same as angle θ2 made between thesecond direction Y and the direction D2.

A sensor electrode Rx is arranged across the pixels PX. In the exampleillustrated, the pixels PX located in the odd-numbered rows along thesecond direction Y are extended in the direction D1. In addition, thepixels PX located in the even-numbered rows along the second direction Yare extended in the direction D2. Incidentally, the pixel PX indicates aminimum unit that can be individually controlled in accordance with thepixel signal, and may be referred to as a sub-pixel. In addition, aminimum unit for realizing color display may be referred to as a mainpixel MP. The main pixel MP is composed of sub-pixels PX displayingcolors different from each other. For example, the main pixel MPcomprises a red pixel which displays a red color, a green pixel whichdisplays a green color, and a blue pixel which displays a blue color asthe sub-pixels PX. Furthermore, the main pixel MP may comprise a whitepixel which displays a white color.

For example, in one sensor electrode Rx, 60 to 70 main pixels MP arearranged along the first direction X, and 60 to 70 main pixels MP arearranged along the second direction Y.

FIG. 4 is an illustration showing a basic structure of the pixel PX andan equivalent circuit.

The scanning lines G are connected to a scanning line drive circuit GD.The signal lines S are connected to a signal line drive circuit SD.Incidentally, the scanning lines G and the signal lines S may not extendlinearly, but may be partially curved or bent. For example, the signallines S are assumed to extend in the second direction Y even if thesignal lines S are partially curved or bent.

The common electrode CE is provided for each of sensor blocks B. Thecommon electrode CE is connected to a voltage supply unit CD of a commonvoltage (Vcom) and is arranged across the pixels PX. In addition, eachof the common electrodes CE is also connected to the touch controller TCas described above and forms the sensor electrode Rx to which the touchdrive voltage is applied in the touch sensing mode.

Each of the pixels PX comprises a switching element SW, a pixelelectrode PE, the common electrode CE, a liquid crystal layer LC and thelike. The switching element SW is composed of, for example, a thin-filmtransistor (TFT) and is electrically connected to the scanning line Gand the signal line S. The scanning line G is connected to the switchingelements SW in each of the pixels PX arranged in the first direction X.The signal line S is connected to the switching elements SW in each ofthe pixels PX arranged in the second direction Y. The pixel electrode PEis electrically connected to the switching element SW. Each pixelelectrode PE is opposed to the common electrode CE, and drives theliquid crystal layer LC by an electric field produced between the pixelelectrode PE and the common electrode CE. A storage capacitance CS isformed, for example, between an electrode of the same potential as thecommon electrode CE and an electrode of the same potential as the pixelelectrode PE.

FIG. 5 is a plan view showing an example of a pixel layout.

The scanning lines G1 to G3 extend linearly along the first direction Xand are arranged in the second direction Y to be spaced apart from eachother. The signal lines S1 to S3 extend substantially along the seconddirection Y and are arranged in the first direction X to be spaced apartfrom each other. In addition, the display panel PNL comprises metallines ML1 to ML3 extending substantially along the second direction Yand arranged in the first direction X to be spaced apart from eachother. The metal lines ML1 to ML3 extend to be overlaid on the signallines S1 to S3, respectively. In addition, although described later,each of the metal lines ML1 to ML3 includes an extended part (secondparts PT2) which is extended to be connected to common electrodes CE1and CE2.

The pixel electrodes PE1 and PE2 are located between the scanning linesG1 and G2. The pixel electrodes PE1 and PE2 are arranged in the firstdirection X. The pixel electrodes PE3 and PE4 are located between thescanning lines G2 and G3. The pixel electrodes PE3 and PE4 are arrangedin the first direction X. The pixel electrodes PE1 and PE3 are arrangedbetween the signal lines S1 and S2, and the pixel electrodes PE2 and PE4are arranged between the signal lines S2 and S3.

The pixel electrodes PE1 and PE2 include strip electrodes Pa1 and Pa2extending along the direction D1, respectively. The pixel electrodes PE3and PE4 include strip electrodes Pa3 and Pa4 extending along thedirection D2, respectively. In the example illustrated, the number ofstrip electrodes Pa1 to Pa4 is three. However, the number of stripelectrodes may be two or less or four or more.

The common electrode CE1 is arranged across the pixels PX1 and PX2. Thecommon electrode CE2 is arranged across the pixels PX3 and PX4. Thecommon electrodes CE1 and CE2 are arranged in the second direction Y.The common electrodes CE1 and CE2 are included in one sensor electrodeRx shown in FIG. 2. The common electrode CE1 is overlaid on the signallines S1 to S3. The pixel electrodes PE1 and PE2 are overlaid on thecommon electrode CE1. The common electrode CE2 is overlaid on the signallines S1 to S3. The pixel electrodes PE3 and PE4 are overlaid on thecommon electrode CE2. In the example illustrated, the scanning line G2is located between the common electrodes CE1 and CE2.

In addition, the common electrode CE1 includes a slit SL1, and thecommon electrode CE2 includes a slit SL2. The slits SL1 and SL2 arelocated on a boundary between the main pixels MP. That is, in the commonelectrode CE1, a part CE1 a overlaid on one main pixel MP is divided bythe slit SL1. Similarly, in the common electrode CE2, a part CE2 aoverlaid on one main pixel MP is divided by the slit SL2. The parts CE1a are connected to each other by a connecting portion CN. Similarly, theparts CE2 a are connected to each other by a connecting portion CN. Theconnecting portion CN of the common electrode CE1 and CE2 is overlaid onthe signal line S1 and the metal line ML1 in the example illustrated. Inaddition, each of the common electrodes CE1 and CE2 includes protrudingportions PR that protrude in the second direction Y, although describedlater. The protruding portions PR are overlaid on extended portions(second portions PT) of the metal lines ML1 and ML2.

In addition, the common electrode CE includes a bridge portion BRlocated between the common electrode CE1 and the common electrode CE2.In the example illustrated, the bridge portion BR is overlaid on thesignal line S3 and the metal line ML3. The bridge portion BR is formedintegrally with the common electrode CE1 and the common electrode CE2 tomake electric connection between the common electrode CE1 and the commonelectrode CE2. The bridge portion BR is included in the sensor electrodeRx, similarly to the common electrode CE1 and the common electrode CE2.

FIG. 6 is a plan view showing shapes of the metal lines ML1 and ML2 anda metal electrode ME of the embodiments.

Each of the metal lines ML1 and ML2 includes a first portion PT1extending in the second direction Y and a second portion PT2 having awidth W12 larger than a width W11 of the first portion PT1. The secondportion PT2 is overlaid on a contact hole CH1 formed in an insulatingfilm 15 to be described later. The second portion PT2 is connected tothe common electrode through the contact hole CH1. The second portionPT2 includes an arcuate first edge EG1 and an arcuate second edge EG2located on a side opposite to the first edge EG1, in planar view. Inaddition, as shown inside frame A of FIG. 6, when the shape of thesecond portion PT2 is represented by a dotted line, the second portionPT2 is formed in a circular shape. Incidentally, the second portion PT2is formed in a polygonal shape larger than four sides. Several sides ofthe sides forming the polygonal shape may be curves. In addition, asshown inside frame B of FIG. 6, the second portion PT2 can be assumed toinclude protruding portions T1 and T2 that protrude from the outer shapeof the first portion PT1. In the example illustrated, the protrudingportions T1 and T2 have a semicircular shape but may have a polygonalshape larger than four sides.

To suppress occurrence of parasitic capacitance between the secondportions PT2 and the metal electrode ME, the second portions PT2 arelocated remote from the metal electrode ME by predetermined distances L1and L2. By forming the second portion PT2 in a circular shape or apolygonal shape having sides more than four sides, the second portionPT2 can be arranged more closely to the scanning line G2 side ascompared with a case where the second portion PT2 has a rectangularshape. In this case, too, the predetermined distances between the secondportions PT2 and the metal electrode ME can be maintained.

The display panel PNL comprises a metal electrode ME located between themetal line ML1 and the metal line ML2 and formed in an insular shape.The metal electrode ME is formed of the same material as that of themetal lines ML1 and ML2. The metal electrode ME is shaped in a polygonhaving n corners where n is an integer larger than four. Incidentally,several sides, of the sides forming the polygonal shape may be curves.In addition, the metal electrode ME may be formed in an elliptic shape.By forming the metal electrode ME in a polygonal shape larger than foursides or an elliptic shape, the second portion PT2 can be arranged muchmore closely to the scanning line G2 side while maintaining thepredetermined distances L1 and L2.

The metal electrode ME has sides E1, E2, E3, E4, E5, and E6. In theexample illustrated, the sides E1 and E4 extend in the first directionX, and the side E1 is formed to be shorter than the side E4. Inaddition, the metal electrode ME is overlaid on a contact hole CH2formed in an insulating film 14 to be described later. The metalelectrode ME is connected to a drain electrode in an insular shapethrough the contact hole CH2. In addition, the metal electrode ME isoverlaid on a contact hole CH3 formed in an insulating film 15 to bedescribed later. The metal electrode ME is connected to a transparentelectrode in an insular shape through the contact hole CH3.

FIG. 7 is a cross-sectional view showing the display panel PNL takenalong line A-B shown in FIG. 6.

The first substrate SUB1 comprises an insulating substrate 10,insulating films 11 to 16, the signal lines S1 and S2, the metal linesML1 and ML2, the common electrode CE1, the pixel electrode PE1, and analignment film AL1.

The insulating substrate 10 is a light transmissive substrate such as aglass substrate or a flexible resin substrate. The insulating film 11 islocated on the insulating substrate 10. The insulating film 12 islocated on the insulating film 11. The insulating film 13 is located onthe insulating film 12.

The signal lines S1 and S2 are located on the insulating film 13. Thesignal lines S1 and S2 are formed of a metal material such as aluminum(Al), titanium (Ti), silver (Ag), molybdenum (Mo), tungsten (W), copper(Cu), or chromium (Cr), or an alloy obtained by combining the metalmaterials, and may have a single-layer structure or a multilayerstructure. For example, the signal lines S1 and S2 are a stacked layerbody formed by stacking a first layer containing titanium (Ti), a secondlayer containing aluminum (Al), and a third layer containing titanium(Ti) in this order.

The insulating film (first organic insulating film or first insulatingfilm) 14 covers the signal lines S1 and S2. The insulating film 14includes a first surface SF1, and a second surface SF2 on a sideopposite to the first surface SF1. The metal lines ML1 and ML2 arearranged on the second surface SF2 of the insulating film 14. Theinsulating film (second insulating film) 15 covers the metal lines ML1and ML2. That is, the metal lines ML1 and ML2 are located between theinsulating film 14 and the insulating film 15. The metal lines ML1 andML2 are formed of the above-described metal material, an alloy formed ofa combination of the above metal materials, or the like, and may have asingle-layer structure or a multilayer structure. For example, the metallines ML1 and ML2 are the stacked layer bodies formed by stacking afirst layer containing titanium (Ti), a second layer containing aluminum(Al), and a third layer containing titanium (Ti) in this order, or thestacked layer bodies formed by stacking a first layer containingmolybdenum (Mo), a second layer containing aluminum (Al), and a thirdlayer containing molybdenum (Mo) in this order. The insulating film 15is provided between the insulating film 16 and the second surface SF2 ofthe insulating film 14.

The common electrode CE1 is located on the insulating film 15. Thecommon electrode CE1 is provided between the insulating film 15 and theinsulating film 16. The common electrode CE1 is in contact with thesecond portion PT2 through the contact hole CH1 formed in the insulatingfilm 15, at the position overlaid on the second portion PT2 of the metalline ML2. The common electrode CE1 is a transparent electrode formed ofa transparent conductive material such as indium tin oxide (ITO) orindium zinc oxide (IZO). The insulating film 16 covers the commonelectrode CE1. Incidentally, in the example illustrated, the commonelectrode CE1 is connected to the metal line ML2. However, the commonelectrode CE1 may be connected to the metal line ML1 or connected toboth the metal lines ML1 and ML2.

The pixel electrode PE1 is located on the insulating film 16 and iscovered with the alignment film AL1. That is, the pixel electrode PE1 isprovided between the insulating film 16 and the alignment film AL1. Thepixel electrode PE1 is a transparent electrode formed of a transparentconductive material such as ITO or IZO. The alignment film AL1 alsocovers the insulating film 16.

Each of the insulating films 11 to 13, and the insulating film 16 is aninorganic insulating film formed of an inorganic insulating materialsuch as silicon oxide, silicon nitride, or silicon oxynitride, and mayhave a single-layer structure or a multilayer structure. Each of theinsulating films 14 and 15 is an organic insulating film formed of, forexample, an organic insulating material such as acrylic resin.

The second substrate SUB2 comprises an insulating substrate 20, thelight-shielding layer BM, a color filter CF, an overcoat layer OC, andan alignment film AL2.

The insulating substrate 20 is a light transmissive substrate such as aglass substrate or a resin substrate, similarly to the insulatingsubstrate 10. The light-shielding layer BM and the color filter CF arelocated on a side of the second insulating substrate 20, which isopposed to the first substrate SUB1. The color filter CF includes a redcolor filter CFR, a green color filter CFG, and a blue color filter CFB.The overcoat layer OC covers the color filter CF. The overcoat layer OCis formed of a transparent resin. The alignment film AL2 covers theovercoat layer OC. The alignment film AL1 and the alignment film AL2 areformed of, for example, a material exhibiting horizontal alignmentproperties.

The first substrate SUB1 and the second substrate SUB2 described aboveare arranged such that the alignment film AL1 and the alignment film AL2are opposed to each other. The first substrate SUB1 and the secondsubstrate SUB2 are bonded to each other by a sealant with apredetermined cell gap formed between the substrates. The liquid crystallayer LC is held between the first alignment film AL1 and the secondalignment film AL2. The liquid crystal layer LC comprises liquid crystalmolecules LM. The liquid crystal layer LC is composed of a liquidcrystal material of a positive type (having positive dielectricanisotropy) or a negative type (having negative dielectric anisotropy).

An optical element OD1 including a polarizer PL1 is bonded to theinsulating substrate 10. An optical element OD2 including a polarizerPL2 is bonded to the insulating substrate 20. Incidentally, each of theoptical element OD1 and the optical element OD2 may comprise aretardation film, a scattering layer, an antireflective layer, and thelike as needed.

In the display panel PNL, the liquid crystal molecules LM are initiallyaligned in a predetermined direction between the alignment film AL1 andthe alignment film AL2, in an off state in which no electric field isproduced between the pixel electrode PE and the common electrode CE. Inthe off state, light emitted from an illumination device IL to thedisplay panel PNL is absorbed by the optical element OD1 and the opticalelement OD2 such that dark display is exhibited. In contrast, in an onstate in which an electric field is produced between the pixel electrodePE and the common electrode CE, the liquid crystal molecules LM arealigned in a direction different from the initial alignment direction bythe electric field, and this alignment direction is controlled by theelectric field. In the on state, part of the light from the illuminationdevice IL is transmitted through the optical element OD1 and the opticalelement OD2 such that bright display is exhibited.

FIG. 8 is a plan view showing a positional relationship among the metallines ML1 and ML2 and the metal electrode ME shown in FIG. 6, and thelight-shielding layer BM.

The light-shielding layer BM includes a first light-shielding portionBM1 overlaid on the scanning line G2 and extending in the firstdirection X, and a second light-shielding portion BM2 overlaid on thesignal lines S1 and S2 and extending in the second direction Y. A firstwidth W21 of the first light-shielding portion BM1 in the seconddirection Y is larger than a second width W22 of the secondlight-shielding portion BM2 in the first direction X. An area surroundedby the first light-shielding portion BM1 and the second light-shieldingportion BM2 corresponds to an opening portion OP of the pixel PX. Thefirst portion PT1 is overlaid on the second light-shielding portion BM2and extends in the second direction Y. In the example illustrated, apart of the first portion PT1 is also overlaid on the firstlight-shielding portion BM1. In addition, the second portion PT2 isoverlaid on the first light-shielding portion BM1. In the exampleillustrated, a part of the second portion PT2 is also overlaid on thesecond light-shielding portion BM2. The metal electrode ME is overlaidon the first light-shielding portion BM1.

The shape of the second portion PT2 may be based on tangent LN1 of angleθ11 to the first direction X, tangent LN2 of angle θ12 to the firstdirection X, and tangent LN3 of angle θ13 to the first direction X. Eachof the angles θ11 and θ12 is 65 degrees or more and the angle θ13 is 70degrees or more. In addition, angle θ21 of the side E3 of the metalelectrode ME to the first direction X, and angle θ22 of the side E5 tothe first direction X are desirably 65 to 75 degrees or more to suppressoccurrence of depolarization. Since the sides E3 and E5 are inclined tothe scanning line G2, an area of the metal electrode ME can be reducedand the parasitic capacitance between the metal electrode ME and thescanning line G2 can be reduced.

For example, when the second portion PT2 has a rectangular shape, thesecond portion PT2 is arranged under the second light-shielding portionBM2 to secure the predetermined distances L1 and L2. However, the secondportion PT2 is overlaid on the opening portion OP of the pixel PX, whichmay reduce the aperture ratio. In addition, when the second portion PT2has a rectangular shape, the parasitic capacitance between the secondportion PT2 and the metal electrode ME may increase and the yields maybe lowered.

According to the embodiments, the outer shape of the second portion PT2is formed in an arcuate shape. Alternatively, the second portion PT2 isformed in a circular shape or a polygonal shape larger than four sides.For this reason, the second portion PT2 can be made closer to thescanning line G2 while maintaining the predetermined distances L1 andL2, and the second portion PT2 can be arranged at the position overlaidon the first light-shielding portion BM1. The above-described reductionin an aperture ratio can be therefore suppressed. In addition,depolarization is often caused by forming the second portion PT2 in acircular shape or a polygonal shape larger than four sides. Since thesecond portion PT2 is overlaid on the first light-shielding portion BM1,reduction of display contrast can be suppressed. In addition, thereduction in yields caused by occurrence of the parasitic capacitancecan be suppressed.

Incidentally, as shown in FIG. 6, the contact hole CH1 of the insulatingfilm 15 may not be formed at the position overlaid on the entire secondportion PT2. In addition, the second portion PT2 may not be formed at aportion which is not connected to the common electrode.

FIG. 9 is a plan view showing shapes of a semiconductor layer SC and adrain electrode DE.

The display panel PNL comprises a drain electrode DE in an insularshape, which is formed of the same material as the signal lines S1 andS2. The drain electrode DE is arranged between the signal lines S1 andS2. The pixel electrode PE is provided at the switching element SW.Incidentally, in the switching element SW, the drain electrode DE isoften referred to as a source electrode. The drain electrode DE isoverlaid on the metal electrode ME in planar view.

The semiconductor layer SC is arranged to be partially overlaid on thesignal line S2, and the other part extends between the signal lines S1and S2 to be substantially shaped in a U letter. The semiconductor layerSC crosses the scanning line G2 at a position overlaid on the signalline S2 and also crosses the scanning line G2 at a position between thesignal lines S1 and S2. In the scanning line G2, areas overlaid on thesemiconductor layer SC function as gate electrodes GE1 and GE2,respectively. That is, the switching element SW of the illustratedexample has a double-gate structure. The semiconductor layer SC iselectrically connected to the signal line S2 through a contact hole CH11at an end portion SCA of the semiconductor layer SC, and is electricallyconnected to the drain electrode DE through a contact hole CH12 at theother end portion SCB of the semiconductor layer SC. The display panelPNL comprises a light-shielding film LS overlaid on a gate electrodeGE2. The light-shielding film LS is also overlaid on a part of the metalelectrode ME and a part of the drain electrode DE.

FIG. 10 is a plan view showing a positional relationship between thedrain electrode DE shown in FIG. 9 and the light-shielding layer BM.

The drain electrode DE is overlaid on the first light-shielding portionBM1. The drain electrode DE includes an arcuate edge DEE (third edge)opposed to the scanning line G2 in planar view. Since the drainelectrode DE includes the arcuate edge DEE, the distance L3 between thedrain electrode DE and the scanning line G2 can be partially increased.For this reason, the parasitic capacitance between the drain electrodeDE and the scanning line G2 can be reduced. Therefore, the reduction inyields caused by occurrence of the parasitic capacitance can besuppressed. In addition, the metal electrode ME covers the edge DEE.Depolarization is often caused by forming the edge DEE in an arcuateshape. The edge DEE is overlaid on the first light-shielding portion BM1but reduction of contrast may be visually recognized from a viewingangle inclined to the third direction Z. In the example illustrated,since the metal electrode ME located in the layer lower than thelight-shielding layer BM is overlaid on the edge DEE, visual recognitionof the reduction of contrast which is caused by depolarization from theinclined viewing angle can be suppressed.

FIG. 11 is a plan view showing shapes of the common electrodes CE1 andCE2 and the transparent electrodes TE.

The transparent electrodes TE are overlaid on the metal electrodes MEand are formed in an insular shape in planar view. In the exampleillustrated, the transparent electrodes TE have an elliptic shape(nonrectangular shape). Incidentally, the transparent electrodes TE maybe in a polygonal shape larger than four sides. Several sides of thesides forming the polygonal shape may be curves. The transparentelectrodes TE are formed of the same material as the common electrodeCE1. The transparent electrodes TE are overlaid on the contact holes CH3formed in the insulating film 15. The transparent electrodes TE areconnected to the metal electrodes ME through the contact holes CH3. Inaddition, the transparent electrodes TE are overlaid on contact holesCH4 formed in the insulating film 16. The transparent electrodes TE areconnected to the pixel electrodes through the contact holes CH4. Thus,the transparent electrodes TE are overlaid on the contact holes CH3 andCH4 and are more elongated in the first direction X than in the seconddirection Y. That is, the transparent electrodes TE are formed in asubstantially elliptic shape (nonrectangular shape) or a polygonal shapehaving n corners where n is an integer larger than four, in a state ofmaintaining the area for arranging the contact holes CH3 and CH4, inplanar view.

Since the transparent electrodes TE are formed in an elliptic shape or apolygonal shape larger than four sides, a distance L4 between thetransparent electrodes TE and the common electrode CE1 and a distance L5between the transparent electrodes TE and the common electrode CE2 canbe increased. For this reason, the parasitic capacitance between thetransparent electrodes TE and the common electrode CE1 and the parasiticcapacitance between the transparent electrodes TE and the commonelectrode CE2 can be reduced. Furthermore, as regards the transparentelectrode TE located adjacent to the bridge portion BR, the parasiticcapacitance between the transparent electrode TE and the bridge portionBR can be reduced. In addition, the reduction in yields caused byoccurrence of these parasitic capacitances can be suppressed.

The metal electrodes ME are located between the common electrode CE1 andthe common electrode CE2 in planar view. The common electrode CE1includes protruding portions PR which protrude to the common electrodeCE2 side. The protruding portions PR are overlaid on the second portionsPT2. In addition, the protruding portion PR is overlaid on the contacthole CH1 at a position overlaid on the second portion PT2 of the metalline ML2. The protruding portion PR is connected to the second portionPT2 through the contact hole CH1. Incidentally, the protruding portionPR may not be formed at the portion where the common electrode CE1 andthe metal line ML are not connected.

FIG. 12 is a cross-sectional view showing the first substrate SUB1 takenalong line C-D shown in FIG. 11.

The light-shielding film LS is formed on the insulating substrate 10 andis covered with the insulating film 11. The first surface SF1 of theinsulating film 14 covers the switching element SW. The semiconductorlayer SC is located on the insulating film 11 and is covered with theinsulating film 12. The semiconductor layer SC is formed of, forexample, polycrystalline silicon, but may be formed of amorphous siliconor an oxide semiconductor.

The gate electrode GE2, which is a part of the scanning line G2, islocated on the insulating film 12 and is covered with the insulatingfilm 13. The gate electrode GE2 is provided on the switching element SW.The scanning line G2 is formed of a metal material such as aluminum(Al), titanium (Ti), silver (Ag), molybdenum (Mo), tungsten (W), copper(Cu) or chromium (Cr) or an alloy obtained by combining the metalmaterials and may have a single-layer structure or a multilayerstructure. For example, the scanning line G2 is formed of a molybdenumtungsten alloy.

The drain electrode DE is located on the insulating film 13 and iscovered with the insulating film 14. The drain electrode DE is incontact with the first surface SF1 of the insulating film 14. The drainelectrode is in contact with the semiconductor layer SC through thecontact hole CH12 formed in the insulating film 13. The metal electrodeME is arranged on the second surface SF2 of the insulating film 14 andis covered with the insulating film 15. That is, the metal electrode MEis located between the insulating films 14 and 15. The metal electrodeME is in contact with the drain electrode DE through the contact holeCH2 formed in the insulating film 14. The transparent electrode TE isarranged on the insulating film 15 and is covered with the thirdinsulating film 16. The insulating film 16 is located on the insulatingfilms 14 and 15. The transparent electrode TE is located between theinsulating films 14 and 16. In addition, the transparent electrode TE islocated between the insulating films 15 and 16. The transparentelectrode TE is in contact with the metal electrode ME through thecontact hole CH3 formed in the insulating film 15. The pixel electrodePE is located on the insulating film 16. The pixel electrode PE is incontact with the transparent electrode TE through the contact hole CH4formed in the insulating film 16. The drain electrode DE, the metalelectrode ME, and the transparent electrode TE are overlaid in the thirddirection Z.

FIG. 13 is a plan view showing a position of the spacer SP. Thestructure shown in FIG. 13 is different from the structure shown in FIG.11 with respect to a feature that the spacer SP is arranged at aposition overlaid on the second portion PT2 of the metal line ML1.

The spacer SP is also overlaid on the protruding portion PR of thecommon electrode CE1. Incidentally, the spacer SP is not arranged at aposition overlaid on the contact hole CH1.

FIG. 14 is a cross-sectional view showing the display panel PNL takenalong line E-F shown in FIG. 13. The structure shown in FIG. 14 isdifferent from the structure shown in FIG. 7 with respect to a featurethat the spacer SP is arranged.

In the example illustrated, the spacer SP is provided in the secondsubstrate SUB2. The spacer SP protrudes to the first substrate SUB1 sideand abuts on the first substrate SUB1. Incidentally, the spacer SP maynot be in contact with the first substrate SUB1. Thus, the spacer SP maybe arranged at the portion where the contact hole CH1 is not formed inthe insulating film 15, at the position overlaid on the second portionPT2 of the metal line ML.

As described above, according to the embodiments, a display devicecapable of increasing the aperture ratio of the pixels can be obtained.

While certain embodiments have been described, these embodiments as usedfor a semiconductor substrate comprising a plurality of thin-filmtransistors, have presented a display device by way of example only, andare not intended to limit the scope of the inventions. Indeed, the novelembodiments described herein may be embodied in a variety of otherforms; furthermore, various omissions, substitutions and changes in theform of the embodiment described herein may be made without departingfrom the spirit of the invention. The accompanying claims and theirequivalents are intended to cover such forms or modifications as wouldfall within the scope and spirit of the inventions.

What is claimed is:
 1. A semiconductor substrate comprising: a switchingelement; a first organic insulating film covering the switching element;a first metal line and a second metal line arranged in a first directionand extending in a second direction intersecting the first direction;and a metal electrode in an insular shape located between the firstmetal line and the second metal line, wherein the first organicinsulating film includes a first surface and a second surface on a sideopposite to the first surface, the switching element is covered with thefirst surface, the first metal line, the second metal line, and themetal electrode are located on the second surface side, the first metalline includes a first portion extending in the second direction and asecond portion having a width larger than a width of the first portion,the second portion includes an arcuate first edge and an arcuate secondedge located on a side opposite to the first edge, in planar view, andthe metal electrode has a polygonal shape having n corners or anelliptic shape where n is larger than four.
 2. The semiconductorsubstrate of claim 1, further comprising: a scanning line extending inthe first direction, wherein the switching element comprises a drainelectrode and a gate electrode which is a part of the scanning line, thedrain electrode is in contact with the first surface of the firstorganic insulating film, the metal electrode is connected to the drainelectrode through a contact hole formed in the first organic insulatingfilm, and the drain electrode includes an arcuate third edge opposed tothe scanning line in planar view.
 3. The semiconductor substrate ofclaim 2, further comprising: an inorganic insulating film located on thefirst organic insulating film; and a transparent electrode in an insularshape located between the first organic insulating film and theinorganic insulating film, wherein the transparent electrode isconnected to the metal electrode, and the transparent electrode has apolygonal shape having n corners or an elliptic shape in planar view,where n is larger than four.
 4. The semiconductor substrate of claim 3,further comprising: an alignment film covering the inorganic insulatingfilm; and a pixel electrode provided between the inorganic insulatingfilm and the alignment film, wherein the pixel electrode is connected tothe transparent electrode through a contact hole formed in the inorganicinsulating film.
 5. The semiconductor substrate of claim 4, furthercomprising: a second organic insulating film provided between theinorganic insulating film and the second surface of the first organicinsulating film, wherein the transparent electrode is provided betweenthe second organic insulating film and the inorganic insulating film,and the transparent electrode is connected to the metal electrodethrough a contact hole formed in the second organic insulating film. 6.The semiconductor substrate of claim 3, wherein the drain electrode, themetal electrode, and the transparent electrode are overlaid on eachother in planar view.
 7. The semiconductor substrate of claim 5, furthercomprising: a common electrode provided between the second organicinsulating film and the inorganic insulating film, wherein the commonelectrode is overlaid on the pixel electrode, and the common electrodeis connected to the first metal line or the second metal line through acontact hole formed in the second organic insulating film.
 8. Thesemiconductor substrate of claim 7, wherein the common electrode is asensor electrode.
 9. A display device comprising: a scanning lineextending in the first direction; a signal line extending in a seconddirection intersecting the first direction; a first insulating filmcovering the signal line; a first metal line arranged on the firstinsulating film and extending while overlaid on the signal line; a metalelectrode in an insular shape arranged on the first insulating film andformed of a same material as the first metal line; a second insulatingfilm covering the first metal line and the metal electrode; a firstcommon electrode located on the second insulating film; and alight-shielding layer including a first light-shielding portion overlaidon the scanning line and extending in the first direction and a secondlight-shielding portion overlaid on the signal line and extending in thesecond direction, wherein the first metal line includes a first portionoverlaid on the second light-shielding portion and extending in thesecond direction and a second portion overlaid on the firstlight-shielding portion and having a width larger than a width of thefirst portion, the first common electrode is in contact with the secondportion through a first contact hole formed in the second insulatingfilm at a position overlaid on the second portion, and the secondportion includes an arcuate first edge and an arcuate second edgelocated on a side opposite to the first edge, in planar view.
 10. Thedisplay device of claim 9, wherein a width of the first light-shieldingportion in the second direction is larger than a width of the secondlight-shielding portion in the first direction.
 11. The display deviceof claim 9, further comprising: a second metal line located between thefirst insulating film and the second insulating film and extending inthe second direction, wherein the metal electrode is located between thefirst metal line and the second metal line and is overlaid on the firstlight-shielding portion, and has a polygonal shape larger than foursides or an elliptic shape.
 12. The display device of claim 9, furthercomprising: a drain electrode in an insular shape overlaid on the firstlight-shielding portion and formed of a same material as the signalline, wherein the metal electrode is in contact with the drain electrodethrough a second contact hole formed in the first insulating film, andthe drain electrode includes an arcuate third edge opposed to thescanning line in planar view.
 13. The display device of claim 12,wherein the metal electrode covers the third edge.
 14. The displaydevice of claim 9, further comprising: a transparent electrode in aninsular shape located on the second insulating film and overlaid on themetal electrode, wherein the transparent electrode is in contact withthe metal electrode through a third contact hole formed in the secondinsulating film and has an elliptic shape or a polygonal shape largerthan four sides.
 15. The display device of claim 9, further comprising:a second common electrode arranged parallel to the second direction ofthe first common electrode, wherein the metal electrode is locatedbetween the first common electrode and the second common electrode inplanar view, the first common electrode includes a protruding portionprotruding to the second common electrode side, and the protrudingportion is overlaid on the second portion of the first metal line. 16.The display device of claim 9, wherein the first insulating film and thesecond insulating film are formed of an organic insulating material.